The present invention relates to the generation of pulses in automatic test equipment (ATE) for testing circuits, such as integrated circuits or circuit boards. More particularly, the present invention relates to generating analog pulse in an analog channel of a mixed-signal tester.
Digital integrated circuit (IC) devices are typically tested by applying to pins of the device a pattern of binary stimulus signals in pre-determined patterns and timing relationships. The test system looks at the resulting digital output signals of the device and compares them to a pre-defined truth table. A pass or fail decision results, depending on whether the bits (1's and 0's) at the device's output pins match the bits of the truth table during each time interval. Test systems for such devices are flexible and programmable to suit the requirements of the type of device to be tested. An example of a high-speed, programmable digital test system is the ITS 9000FX system, available from Schlumberger Technologies of San Jose, Calif.
Other devices to be tested are not purely digital. Such devices, known as mixed-signal devices, can have both digital and analog signal characteristics. Mixed-signal devices are mostly digital, but cannot be tested the way purely digital devices are tested.
The networking and data storage markets have recently seen the introduction of devices capable of handling high speed (&gt;100 Mbps) serial data. The data are usually corrupted by physical interactions occurring in the transmission link or in the process of storing and retrieving the data.
One function of receivers for such data is to recover the original information by means of complex analog and/or digital processing and to present the result in digital form. For this reason they are considered mixed-signal devices.